Divided by basic functions, a general computer usually includes an input unit, an output unit, and a processing unit. At present, the most important input units of a computer are nothing more than a keyboard and a mouse, and the monitor is the most important output unit.
The structure of a keyboard comprises a plurality of keys, and each key represents one or more specific character (including a symbol, a text, or a number). Many keys adopt the bitmapped structure; after a user presses a key, the keyboard microcontroller (MCU) will generate a character code corresponding to this key, and then send the character code to the computer system. The signal of such character code will be decoded by the central processing unit (CPU) and the software in the computer system, and then saved in the memory unit (such as a hard disk) or sent to the monitor microcontroller for the processing or conversion, and finally displayed on the monitor.
For those familiar with the keyboard operation, it is not necessary to focus on the keyboard position to enter data, but our vision can stay on the display content of the monitor. On the other hand, for those unfamiliar with the keyboard position, it is necessary to look back and forth at the keyboard position and the data displayed on the monitor frequently to assure the accuracy and consistency of the data during the process of entering data. This method requires the user to look back and forth between the key position of the keyboard and the data displayed on the monitor, which not only causes inconvenience to the operation, but also causes tiredness or even injury easily.
In the R.O.C. patent application No. 89122574 entitled “Keyboard with display device”, a keyboard having a display device on the external casing of the keyboard was disclosed, and its basic technical measure is to add a display device to a traditional keyboard. With the control of a control circuit in the keyboard, after any key is pressed, the symbol representing such key will be displayed on the display device on the external casing of the keyboard and the peripheral device (computer system or notebook computer) connected to the keyboard. The foregoing patented technology has made a slight improvement on the traditional keyboard to solve the inconvenience on the aforesaid application.
However, as to the foregoing patented technology or the traditional keyboard design, all keyboards regardless of being connected to a computer system a by cable or by wireless transmission technology (such as the wireless transmission or infrared transmission have to be in connection with the computer before it can enter data. Once the keyboard is disconnected with the computer system, it is unable to enter or save data into the computer system even if the data is entered from the keyboard. Thus, the traditional keyboard does not have the working capability when it is disconnected.